The federal agency filed a request Monday in federal court, asking to be included as a plaintiff in the lawsuit filed in April by the Southern Poverty Law Center contending the jail's conditions violate the U.S. Constitution.

The Justice Department has been investigating Orleans Parish Prison since 2008. The federal agency says the jail doesn't provide proper medical and mental health care to prisoners and fails to protect prisoners from physical and sexual violence.

In a statement, Thomas Perez, an assistant attorney general for the Justice Department, says he's hopeful federal officials can negotiate a settlement with Gusman.